GFS really tries to throw some of us some token flakes at the end of that system around the 7th just to wet our appetites
Sent from my SM-G920V using Tapatalk
Sent from my SM-G920V using Tapatalk
-
Hello, please take a minute to check out our awesome content, contributed by the wonderful members of our community. We hope you'll add your own thoughts and opinions by making a free account!
Pattern December, Make analogs relevant again
- Thread starter GaWx
- Start date
-
- Tags
- inspired by mack
And with this look it's not entirely out of the question...
Sent from my SM-G920V using Tapatalk
Webberweather53
Meteorologist
This GFS run ought to be very entertaining. As if this pattern wasn't good enough, here comes a pair of typhoons in the Western Pacific, incubated by the CCKW currently over the eastern IO and Maritime continent, trying to recurve into the longwave trough over eastern Asia. The already heavily blocked downstream wave pattern over the North Pacific-North America would only amplify further if these typhoons come to fruition... Lmao.
Webberweather53
Meteorologist
The diabatically-induced upper level ridge NE of the WP typhoon pair is something to behold. You thought the pattern was amplified and blocky in the coming few weeks, you should see what happens if these typhoons get added to the mix...
Snowflowxxl
Member
Big storm coming at hour 384 on GFS lol
whatalife
Moderator
Webberweather53
Meteorologist
Nice to see this Alaskan ridge in most NWP (including the GFS op) seeding North America more quickly with Siberian air after the 1st week of the month like it did in 2013-14/2014-15. The cross polar flow on the eastern flank of that 1059 high over the Pacific side of the arctic circle is great to see... *Pants bursted*
whatalife
Moderator
Sent from my iPhone using Tapatalk
Glad to see the euro control and GFS on the same page...LOL!
Sent from my iPhone using Tapatalk
Parker
Member
Welp, that run was entertaining. Hoping that is the first of many runs that show something big. I’d like to have a monster storm under 200 hours though. Maybe the end of that run is what this pattern could possibly produce
Last edited:
We get it! Cold and dry! Deadhorse
Yay! Rain
Sent from my iPhone using Tapatalk
Jon
Member
The Euro control often does a great job at sniffing out epic cold pushes before the means or Op get a handle on them (or even before the Op shows the cold). I’ve seen this in past years sniffing out PV lobe break offs. I use the control a lot during winter for this reason.
Sent from my iPhone using Tapatalk
Webberweather53
Meteorologist
Some of the models are starting to drift towards a solution where the main cold gets blocked behind the Apps and dives to the gulf coast, hence the overrunning on the GFS! That would be a kick in the pants
NorthGaWinter4
Member
Woah GEFS has a few snowy members in the 10 day range. Folks we might have something to watch
That run is just one of numerous possibilities and it does give a major snow to some of our more western members. It isn't easy to get something pretty board-wide like 1/1988 and this run illustrates that well. Regardless, I'd rather the main trough to be centered near the MS River as opposed to directly over the SE US as that would allow for a much better chance for moist upper level WSW to flow over the top of cold air at the surface and the chance for a major storm as opposed to the typical cold and dry when the trough is centered overhead. There is always a fine balance needed for a near boardwide major winter storm because too much moist SW upper flow could lead to too much surface warming.
NWMSGuy
Member
Well that was a fun run! Let's keep them up! :weenie:
Webberweather53
Meteorologist
The background state w/ negative Atmospheric Angular Momentum dominating the mid-latitudes, a strong subtropical jet core, hastened by a equatorward propagating and strong wave train (which derived its energy in part from the once very persistent and strong planetary scale ridge over the Aleutians) over the western hemisphere, in addition to proper placement of these waves in the troposphere (superimposed onto the mean mid-upper level planetary waves) is disrupting the polar vortex and all of this I just mentioned is already helping to establish and "lock in" the blocking we're currently seeing (& about to see) over the North Atlantic, North Pacific, and Arctic.
In summary, we already have a damn good pattern and background forcing for creating sustainable, long-term high latitude blocking. A typhoon recurvature working in conjunction with a slow-moving, convectively coupled kelvin wave through diabatic heating (released via large-scale condensation processes in the typhoons) and geostrophic adjustment of the subtropics and mid latitudes in response to this tropical heating source would force a huge rossby wave packet emanating downstream from the typhoons which would further amplify an already amplified pattern over our neck of the woods. In essence, this means an already cold pattern could get even colder...
A good analogy to what I just described is think of the typhoons and the response in the mid latitudes like throwing a gigantic rock into a lake. When it's relatively still, as is often the case (except now), it creates pretty large ripples that disperse outward in all directions and are easily traceable... (akin to ageostrophic geopotential flux & Rossby wave dispersion that propagates the Rossby Wave packet downstream from the heating source generated by the typhoons in West Pacific to other parts of the world like North America). However, what if say, there are other boats speeding thru the lake that have already created a bunch of big waves and the water in the lake is more turbulent to begin with? This kind of like how the mid-latitude -AAM, tall/persistent Aleutian ridge, and planetary wave alignment in an attempt to destroy the polar vortex, have aligned to create this amplified pattern here in the Western Hemisphere. Then, you decide throw the gigantic rock into the lake, what do you think is going to happen to the waves that have already been stirred up by the boats? The waves generated by the rock and the boats will interfere with one another and the amplitude of the waves and crests of the highest waves will increase, although some waves may completely disappear due to destructive interference w/ one another.
This animation from PSU illustrates this aforementioned wave interference pattern pretty nicely. You can relate to this what we observe in real time w/ the top, stationary wave representing the quasi-stationary, low frequency, and large planetary waves and the middle, moving wave to represent the more transient, faster moving mid latitude disturbances, and the third wave pattern on the bottom shows what is actually observed. Notice when the stationary and relatively fast moving waves align w/ one another, the amplitude of the observed wave increases and vis versa. This is analogous to what I'm trying to say here, in that the Rossby Wave train that's generated by the Western Pacific typhoons could lead to even larger troughs and ridges downstream here because if the waves embedded within the Rossby Wave packet align w/ the quasi-stationary planetary waves then they'll constructively interfere w/ one another, causing the observed wave pattern to become more amplified (& "blocky" in this case).
This image of 200 hPa stream function shows what happens when a remote tropical heating source in the central Pacific forces downstream parade of Rossby Waves... Note the waves veer poleward and then are deflected to the east, this is due to the stronger influence of the coriolis force in the mid-high latitudes. Also notice that the amplitude of the waves (which represent troughs/ridges) decreases w/ distance away from the tropical source, processes such as friction, damping due to diabatic or solar heating, and dispersion, among others explain why this is the case.
(As an aside streamfunction is essentially like geopotential height you see on an every day 500 hPa height map, except the flow is purely non divergent. So in essence, it's showing you height contours, but unlike w/ geopotential height on an isobaric (equivalent pressure surface) where the winds can cross height contours, here the winds are perfectly aligned with the height contours. Sometimes you'll often see streamfunction and another more well recognized variable (velocity potential) shown on sigma surfaces (like .2101 sigma for ex), it's a height surface except its corrected for surface elevation. So unlike pressure which can dip under tall mountain ranges like the Rockies or Himalayas (like the 850 hPa surface for ex), sigma surfaces don't do that)
